This invention relates to a message storing and reproducing system and, more particularly, to a system which is of the type described and is connected to a message exchange network for a plurality of subscriber sets or subscribers and which comprises a predetermined number of message storages for storing messages or voice sequences from certain ones of the subscriber sets for reproduction.
When the messages are the voice sequences, the message storing and reproducing system is often called a voice storing and reproducing service system and will so be referred to herein. The message exchange network is in this case a telephone exchange network that is typically a public telephone network and may alternatively be a mobile communication exchange network accommodating mobile units as at least a part of the subscriber sets.
In the manner described in greater detail below, a conventional voice storing and reproducing service system comprises a preselected number of voice processing and storing units connected to the telephone exchange network. Each voice processing and storing unit comprises a memory which may be a memory area of a memory unit common to parts of the voice storing and reproducing units.
It will be assumed that one of the subscribers wishes as an originating subscriber to enjoy a service of the voice storing and reproducing service system. Sent through the exchange network by the originating subscriber by using his subscriber set, an originating voice sequence is processed by one of the voice processing and storing units into a message datum to be stored therein as a stored message. As a consequence, this one of the voice processing and storing units is assigned to the originating subscriber as an assigned voice processing and reproducing unit. When the originating subscriber sends a reproducing request which specifies one of the subscribers as a specified subscriber, the assigned voice processing and storing unit reads the stored message as a read message and processes the read message into a reproduced voice sequence to send the reproduced voice sequence through the message exchange network to one of the subscriber sets that is attended to by the specified subscriber. In this manner, the service includes storage and reproduction of a voice sequence and may further comprise cancellation and other processing functions of the voice sequence.
In the conventional voice storing and reproducing service system, the originating subscriber can not access other voice processing and storing units from one to another while enjoying the service with the voice processing and storing unit assigned to him. For example, the originating subscriber can not reproduce a stored datum from one of the voice processing and storing units that is not assigned to him.
It should be noted in this connection that each voice processing and storing unit must be operable in various manners and is liable to a fault. If the fault is present in the assigned voice processing and storing unit, complicated switching must be carried out among the voice processing and storing units.
A voice mail information transfer system is disclosed in Japanese Patent Prepublication (A) No. 208,749 of 1992. A voice file reproduction system is revealed in Japanese Patent Prepublication (A) No. 236,006 of 1993. A voice mail system for a plurality of groups of subscriber sets was invented by Shin-ichi Matsuoka, assignor to the present assignee, and filed Feb. 27, 1996, in the United States as patent application Ser. No. 08/607,460. Each of these three prior art systems is operable as a voice storing and reproducing service system and yet has the above-mentioned defects. The system of Matsuoka is, however, provides excellent operation when the subscriber units are operable with different traffic. The specification of the Matsuoka patent application is therefore incorporated herein by reference.